New dynamical nonlinear mechanism, a way to enhance nonlinear efficiency and detect ultrafast electronic processes in photonic crystals

We quantitatively investigate the energy efficiency and the possibility of detecting the electronic ultrafast processes of a new dynamical nonlinear mechanism suitable for the nonlinear photonic crystal switching effect with femtosecond pumping. It is found that the energy efficiency of the new dynamical nonlinear mechanism is considerably higher than traditional band-gap shift mechanism, and the characteristics of the transmission curve are related to the parameters of the electronic ultrafast processes. Thus, the dynamical nonlinear mechanism is a new way to enhance the nonlinear efficiency and to indirectly detect the electronic femtosecond or even attosecond processes. Besides that, the totally new patterns of transmission and reflection spectra revealed in this work also imply the deep differences between two mechanisms. Wide potential usages could be expected for the properties found by this work.